In a regular transmission, thus a manual transmission, or an automatic transmission, the actions “lay gear out”; “select” and “shift gear” take place in this predetermined sequence. In a transmission, comprising an active interlock shifting mechanism, the functions of laying the gear out, and shifting the gear, are performed through different structural components, in particular, shifting is performed through shifting fingers, which are only being used for shifting the gears. The laying out is performed through layout geometries, in turn, comprise a layout finger and a layout cam, moving the shifting rod, depending on the shifting process. The shifting geometry, this means the shifting fingers, and the layout geometry, are separate components, so that the selection movement for the target gear can be performed before the layout movement of the initial gear performed.
Thus, in an active interlock shifting mechanism, the shifting finger can be moved back into the middle position, when a gear is shifted, without laying out the current initial gear. Thus, the new gear can be selected, before the old gear is laid out. In all shift alleys, in which the shifting finger is not positioned, a layout geometry operates to lay out the initial gear. It lays out the initial gear directly prior to a new gear being shifted by the shifting finger. Thereby, the shifting finger and the layout geometry are geometrically associated by design, so that an active gear lock is provided, so that a target gear cannot be shifted, before the initial gear is laid out.
Shifting systems with active interlock generally comprise error recognition systems, which cause a control system for an automated transmission to bring the transmission into a safe state through mechanisms, which are not influenced by the detected error, this means into a state, which is not dangerous for the respective driving condition, and which possibly avoids damages to the transmission. Such occurring errors can be a broken or damaged shifting finger, a broken or damaged layout mechanism, in particular, a broken or damaged layout cam, or other mostly mechanical failures of the gear-shifting mechanism. Furthermore, the errors can relate to test functions, which are being performed, in order to detect the safe shifting of a target gear, or the return of shifting mechanism elements into their initial positions.
Conditions can be problematic, however, in which a failure at an element of the shifting mechanism has e.g. occurred, which, however, has not been detected yet by the transmission control system, so that an error handling mode of the transmission control system is not yet activated, and the control operates in error free operating mode, in spite of the present damage.